When Does it become Medical Neglect?

When does what a parent does or does not do rise to the level of medical neglect, enough for a judge to limit visitation or make one parent sole custodian?
Parent 1 refuses treatment for an infant with a bloody rash for a day and the other parent 2 upon pick up must take the infant to the emergency room
Parent 1 does not give all doses of prescribe medication on 2 occasions
Parent 1 on at least 4 occasions drops child off sick with a fever, leaving the other parent to take child the same day to the doctor.
Parent 1 refuses to take child to a well child check up and says they will reschedule it because it is on their time.
Parent does not show up to important specialist appointment then attacks the other parent for making a decision that affected the development of the child.
Parent 1 gives parent 2 several weeks worth of attacking text messages about child’s surgery, parent 1 says they will be taking up all of the time that child would be awake because parent 2 will have friends there also. Parent 1 does not show up to said surgery.
2 days after said surgery Parent 2 gives parent 1 a prescription to fill because doctor gave parent 2 an extra amount that lasted until parent 1’s visitation. Parent 1 refuses to fill the prescription. After consideration and being attacked in text that it was her responsibility not parent 1’s to fill the prescription, Parent 2 attempts contacting the other parent asking if the prescription has been filled, parent 1 refuses to answer. Instead the only answer parent 2 got was that parent 1 had gotten some chocolate.
The advice of CPS was to offer Parent 1 to give child’s insurance info to his nearest pharmacy. But again parent 1 did not answer. This medicine particularly is to keep the child from having to go back for surgery on the ears again. The doctor was very specific that it must be done, yet parent 1 does not seem to care.

I know that’s probably a little extreme but I did not want to draw out names as much as I’d like to. But the parent that has been responsible for everything has become sick of the others garbage and see’s no end in sight of the spiteful instigation and it is affecting the child.

The court requires only a change in circumstances, not an extreme change. If your child is not doing well in the care of your ex, and there are medical needs that weren’t attended to, that may qualify as a substantial change. Whether this would be considered neglect would depend on a number of factors, but I think you might have a claim for primary or sole custody. Certainly this would be relevant information in a custody action.